Boeing software developers tied plane sensor malfunction alerts to optional sensor displays. It took two crashes and hundreds of human casualties before Boeing took addressed the issue discovered back in 2017. In 2017, Boeing unexpectedly discovered that one of the warning indicators in its newest 737 MAX jet was not working. This was to be a standard feature on all 737 MAX planes. Instead, Boeing performed an internal review and deemed the AOA warning disagreement non-crucial and scheduled a fix for 2020 when a new version the MAX 10 was scheduled to be rolled out.

Source: Ethiopian News June 07, 2019 21:56 UTC